This invention relates to digital data transmission systems, and more particularly to scramblers and descramblers employed therein.
It is a requirement in many data transmission systems that the data to be transmitted, over repeatered lines for example, have certain well defined characteristics which are helpful in the design of the system, such as a suitable distribution of transitions under all normal conditions to aid in the recovery of clock rates from the incoming signals at the receiver.
Typically a data scrambler or descrambler comprises a linear sequential filter with feedback or feedforward paths, respectively, and tapping connections to the feedback or feedforward path, the nature and disposition of the tapping connections being determined in accordance with a polynomial expression which is the same for a matched scrambler and descrambler.